Polycythaemia Flashcards
What is polycythaemia?
Raised red blood cell count
Raised haemoglobin
Raised haematocrit
What is haematocrit?
The volume or percentage of RBC in the blood
What’s a normal haematocrit?
45% men
40% women
What is the cause of primary polycythaemia?
Myeloproliferative disorder such as:
Polycythemia rubra vera
Essential thrombocytosis
Types of leukaemia
What is polycythaemia rubra vera?
Often caused by a genetic mutation - JAK2
Myeloproliferative disorder caused by clonal proliferation of a marrow stem cell leading to an increase in red cell volume
Often accompanied by overproduction of neutrophils and platelets.
What is essential thrombocytosis?
Occurs when the body produces too many platelet cells, which help blood to clot
What is idiopathic myelofibrosis?
The marrow produces too much collagen or fibrous tissue in the bone marrow
This reduces bone marrow’s ability to produce blood cells.
Often occurs secondary to polycythaemia vera
What are some causes of secondary polycythaemia?
Raised serum erythropoietin
Smoking
High altitude
Chronic lung disease
What does erythropoietin do?
It stimulates RBC production
Investigations of polycythaemia?
Blood:
- low serum
- raised Hb, RBC, haematocrit
Bone marrow:
- hypercellular
Symptoms of polycythaemia?
Tiredness Vertigo Visual disturbance Itching after hot bath Angina Intermittent claudication
What complications are there of polycythaemia?
Thrombosis
Clotting, causing strokes, MI, claudication
Why does polycythaemia cause intermittent claudication?
It causes thrombosis
Clots can get into vessels in the legs or arms, causing intermittent claudication
Treatment of polycythaemia rubra vera?
Venesection: removal of some blood to return levels of RBCs to normal
Hydroxycarbamide
Aspirin: for thrombosis
Phosphorus-32 therapy
How would you treat secondary polycythaemia?
If it had been caused by raised EPO, give a drug to counteract this
Stop smoking
